Method for the production of a deck slab for a bridge

ABSTRACT

“A method for producing a construction section of a deck slab for a bridge includes the following operations: producing a bottom layer composed of a segment and having cross beams, which are arranged in the transverse direction in regard to the longitudinal axis of the longitudinal bridge girder, from reinforced concrete; transporting the bottom layer having the cross beams for a construction section of the deck slab using a conveyor device from an assembly site to an installation site and lowering it into the installation position; producing a top concrete layer for a construction section of the deck slab on the bottom layer; removing the bottom layer having the cross beams for a construction section of the deck slab from the conveyor device and moving the conveyor device away from the installation site.”

The invention relates to a method for producing a deck slab using aconveyor device with a top concrete layer produced at the installationsite for a bridge as well as deck slabs produced according to thismethod.

The production of a deck slab for a bridge using a formwork carriage isdescribed in the “Handbuch Brücken”, section 9.3.2 “Schalung andFertigung Betonfahrbahnplatte”, published by Gerhard Mehlhorn with theSpringer-Verlag in the year 2010. There are mounted supportconstructions on the longitudinal bridge girder. On the top surface ofthe support construction, there are installed launching gantries, whichprovide movement of a formwork carriage in the longitudinal direction ofthe bridge. For the production of a construction section of the deckslab, the formwork carriage is conveyed to the installation site, beingfixed there. Subsequently, the formwork for the construction section tobe erected of the deck slab is moved into the scheduled position, thereinforcement is laid and concrete is being introduced. After theconcrete has hardened, the formwork is then lowered and the formworkcarriage is moved to a further installation site. A construction sectionusually has a length of 15 m to 35 m. An advantage of this method isthat in the final condition, there will be present only a few sectionaljoints within the deck slab. A disadvantage of this method is the slowconstruction progress as the assembly of the formwork and the laying ofthe reinforcement are carried out at the installation site and theformwork will only then be removed from the formwork carriage if theconcrete of the construction section last produced has sufficientrigidity. The production of the construction sections using this methodis usually realized within one week, wherein the weekend is used for theconcrete to harden.

The production of the deck slab for a bridge using a formwork carriage,which may be moved directly on the longitudinal bridge girder, isdescribed in the DE 195 44 557 C1. In this method, the effort forproducing the support constructions and for mounting the launchinggantries is being omitted. Also in this method, there is given thedisadvantage of the slow construction progress of a weekly schedule forthe production of a construction section of the deck slabs.

In DE 25 20 105 A1 there are described prefabricated elements made fromreinforced concrete, which are composed of a prefabricated bottom slaband at least one cross beam. In the prefabricated bottom slab, there arearranged the lower transverse reinforcement and the lower longitudinalreinforcement of the deck slab. The prefabricated elements are moved atthe installation site using a crane onto the longitudinal bridge girder.Then the splice reinforcement for the lower longitudinal reinforcement,the upper longitudinal reinforcement and the upper transversereinforcement is being laid. In the next operation, the top concretelayer is then applied. Moving the prefabricated elements at theinstallation site, sealing the joints in-between the individualprefabricated elements and laying of the reinforcement aretime-consuming operations, which is disadvantageous for a fastconstruction progress in the production of the deck slab.

To accelerate construction progress, there is described inWO/2016/187634 A1 a method for producing a deck slab havingprefabricated bottom slabs and a top concrete layer arranged above madefrom in-situ concrete for a bridge having a longitudinal bridge girder.In this method there is produced a conveyor device, which may be movedon support constructions, which are mounted on the top surface of thelongitudinal bridge girder, in the longitudinal direction of the bridge.Using the conveyor device, the prefabricated slabs are transported froman assembly site to an installation site. At the installation site, theprefabricated slabs are lowered until the edges of the prefabricatedslabs are supported on the longitudinal bridge girder. Upon lowering,the prefabricated slabs are still attached at the conveyor device bymeans of tendons. Subsequently, there is laid a reinforcement and a topconcrete layer is applied. After the top concrete layer has hardened,the anchors of the prefabricated slabs are then removed from thetendons. Subsequently, the conveyor device is then moved to an assemblysite to optionally pick up further prefabricated slabs. The disadvantageof the method described in WO/2016/187634 A1 is the anchoring of thetendons within the prefabricated slabs. The load capacity of the anchorsof the tendons is low if anchoring of the tendons is realized within theprefabricated slabs. The load capacity of the anchors of the tendons issufficient if anchoring of the tendons is realized at the bottom surfaceof the prefabricated slabs. Anchoring at the bottom surface of theprefabricated slabs, however, requires an additional operation forremoving the anchors from the bottom surface of the prefabricated slabs.In the method described in WO/2016/187634 A1 it is furthermoredisadvantageous that the forces arising within the tendons cause bendingmoments within the prefabricated slabs, which lead to high bendingstress within the thin prefabricated slabs. A further disadvantage ofthe method described in WO/2016/187634 A1 is that the tendons may onlybe removed from the conveyor device after the top concrete layer hassufficient rigidity. Awaiting the hardening phase of the top concretelayer is disadvantageous for a rapid construction progress in theproduction of the deck slab.

Also the documents AT 520 614 A1 and KR 101 866 466 B each show methodsfor the production of deck slabs of a bridge. There are respectivelypositioned slab-like elements onto longitudinal girders of the bridge,whereupon a reinforce concrete slab will be produced thereon. Themethods of these publications have the same disadvantages as the methodof the publication WO/2016/187634 A1.

The publication JP 2004 116060 A discloses a method, in which there arelaid prefabricated cross beams made from reinforced concrete on alongitudinal bridge girder in order to produce a deck slab.Subsequently, there are laid prefabricated slabs made from reinforcedconcrete on the cross beams. In the next work step, a reinforcement islaid on the prefabricated slabs and then there is applied a top concretelayer. Laying the individual cross beams and subsequently laying theindividual prefabricated slabs at the installation site is timeconsuming and, hence, disadvantageous for a rapid construction progress.

It is thus the task of the present invention to create a method for theproduction of a deck slab, which provides for a faster constructionprogress than with methods known performing formwork and/orreinforcement works at the installation site and in which in theconstruction condition an easier anchoring of the tendons is possibleand in which the bending stress arising in the construction conditionmay be better absorbed than with the method known using prefabricatedbottom slabs.

The task is solved by a method for the production of a constructionsection of a deck slab for a bridge, wherein:

-   -   a—there is produced at an assembly site from reinforced concrete        a bottom layer composed of at least one segment and having cross        beams, which are arranged at an angle of between 70° and 90° to        a longitudinal axis of a longitudinal bridge girder;    -   b—the bottom layer having the cross beam is transported for the        construction section of the deck slab using at least one        conveyor device from the assembly site to an installation site        and lowered into an installation position;    -   c—there is laid onto the bottom layer having the cross beams a        top concrete layer for the construction section of the deck        slab, wherein there is optionally laid a reinforcement to be        arranged within the top concrete layer before the application of        the top concrete layer;    -   d—the bottom layer having the cross beam is removed for the        construction section of the deck slab from the conveyor device        before or after the application of the top concrete layer.    -   e—the conveyor device is moved away from the installation site        and optionally conveyed to the assembly site in order to pick up        there a further bottom layer having cross beams for a        construction section of the deck slab.

To accelerate constructional progress, it may be advantageous toconfigure the bottom layer having the cross beams or a segment of thebottom layer to be load-bearing such that it may absorb its own weightand the weight of the top concrete layer and introduce these into thelongitudinal bridge girder. In this case, the conveyor device may bemoved away from the installation site immediately upon lowering of thebottom layer.

To enlarge the load capacity of the bottom layer, there are arrangedcross beams within the bottom layer. These cross beams may be laid atthe assembly site onto a formwork or a scaffolding before the productionof the bottom layer. The cross beams are advantageously equipped withstarter bars. In this way, a load-bearing connection of the cross beamsto the bottom layer and the top concrete layer is being ensured. Theremay be arranged anchors for lifting the bottom layer and cladding tubesfor tendons within the cross beams. The cross beams may be equipped withsteel slabs to provide for a structural steel connection of the crossbeams to the bottom layer or of cross beams, which are arranged indifferent segments. The connection between cross beams and prefabricatedslabs or between two cross beams, respectively, which are arranged indifferent segments of the bottom layer, may be produced by welding,screwing or by starter bars and hardcore filling.

There may be arranged terminal anchors and deflection points for tendonsin a cross beam. It may be advantageous to produce the top concretelayer in two operations. The second part of the top concrete layer isonly produced after the first part of the top concrete layer has reacheda predefined minimum rigidity. In this case, the bottom layer may beremoved from the conveyor device, after the first part of the topconcrete layer has reached a predefined minimum rigidity. The bottomlayer may be produced having haunches and variable thickness. A segmentof a bottom layer may be shifted transversally to the longitudinal axisof the longitudinal bridge girder and/or rotated in regard thereto afterit has been raised at the assembly site, may be transported from theassembly site to the installation site in this shifted and/or rotatedposition and may then be installed at the installation site by crossshift and/or rotation into the scheduled installation position. It maybe advantageous to transport the segments of the bottom layer for aconstruction section of the deck slabs in several transport operationsfrom the transfer site to the installation site.

In an particularly advantageous embodiment of the present inventionthere is connected a bottom layer composed of at least two segments andhaving cross beams at the assembly site by a first top concrete layer orby other means such as, for example, screw connections, to a bottomlayer composed of one segment.

In a particularly advantageous embodiment of the present invention thebottom layer having cross beams is produced at the assembly site from asegment and transported using a conveyor device composed of a frontpart, a rear part and at least two longitudinal girders from theassembly site to the installation site. The front part and the rear partof the conveyor device are connected to one another by means of the atleast longitudinal girders. The conveyor device is moved along thebridge on support constructions. The bottom layer having the cross beamsduring transport from the assembly site to the installation site isarranged between the front part and the rear part and underneath thelongitudinal girder of the conveyor device. Underneath the bottom layerhaving cross beams, there must not be arranged any constructionselements for connecting the front part and the rear part of the conveyordevice during the lowering operation at the installation site. Duringthe transport of the bottom layer from the assembly site to theinstallation site, it may be useful to connect the front and the rearpart of the conveyor device by way of construction elements such as,e.g., ropes, which are arranged underneath the bottom layer having thecross beams, in order to enlarge the rigidity of the conveyor device.

In a preferred embodiment of the invention the conveyor device isproduced from a front part, a rear part and at least two longitudinalgirders. To shift the conveyor device in order to enable the productionof the next construction section of the deck slab, the front part andthe rear part of the conveyor device are moved on support constructions.The front and the rear part of the conveyor device are connected to oneanother by at least two longitudinal girders. At the longitudinalgirders, there is installed a construction by means of which liftingand/or lowering of the bottom layer having cross beams, which isarranged between the front and the rear part and underneath thelongitudinal girders of the conveyor device, is made possible.

The conveyor device may be configured as a frame construction or as atruss construction.

Using the method according to the invention it is made possible toproduce the deck slab of bridges that are straight in plan view and haveany curvature. Using the method according to the invention it is madepossible to produce deck slabs having any transversal inclination andhaving variable width.

In a further aspect of the invention there is created a constructionsection of a deck slab, comprising a bottom layer composed of at leastone segment and having cross beams, which are arranged at an angle ofbetween 70° and 90° to the longitudinal axis of a longitudinal bridgegirder, wherein the bottom layer is produced from reinforced concreteand wherein onto the bottom layer having cross beams there is applied atop concrete layer for the construction section of the deck slab, whichoptionally has reinforcement.

Further details, features and advantages of the invention become obviousfrom the explanations given below of exemplary embodiments schematicallydepicted in the drawings FIG. 1 to FIG. 39 . The drawings show:

FIG. 1 a view of a first embodiment according to the invention aftercross beams have been laid on a framework at an assembly site;

FIG. 2 a view of the first embodiment according to the invention afterthe bottom layer has been produced for a construction section of thedeck slab on the framework;

FIG. 3 a view of the first embodiment according to the invention whilethe conveyor device is conveyed to the assembly site;

FIG. 4 a view of the first embodiment according to the invention whilethe bottom layer having cross beams is lowered for a constructionsection of the deck slab at the installation site;

FIG. 5 a vertical sectional view according to the section plane V-Vindicated in FIG. 4 ;

FIG. 6 a vertical sectional view according to the section plane V-Vindicated in FIG. 4 after the bottom layer has been lowered at theinstallation site;

FIG. 7 the detail A of FIG. 5 ;

FIG. 8 the detail B of FIG. 6 ;

FIG. 9 a view of the first embodiment according to the invention afterthe top concrete layer has been applied;

FIG. 10 a view of the first embodiment according to the invention whenthe conveyor device is moved from the installation site to the assemblysite;

FIG. 11 a longitudinal view of the first embodiment according to theinvention after the bottom layer having cross beams has been producedfor a construction section of the deck slab at the assembly site;

FIG. 12 a longitudinal view of the first embodiment according to theinvention after the bottom layer having cross beams has been depositedat the installation site;

FIG. 13 a longitudinal view of the first embodiment according to theinvention after the deck slab has been completed;

FIG. 14 a view of a second embodiment according to the invention afterthe bottom layer composed of three segments and having cross beams hasbeen produced on a formwork at an assembly site;

FIG. 15 a view of the second embodiment according to the invention afterthe three segments of the bottom layer having cross beams have beenlowered at the installation site;

FIG. 16 a longitudinal view of the second embodiment according to theinvention after a bottom layer having cross beams has been produced atthe assembly site;

FIG. 17 a longitudinal view of the second embodiment according to theinvention after the bottom layer having cross beams has been depositedat the installation site;

FIG. 18 a longitudinal view of the second embodiment according to theinvention after the deck slab has been completed;

FIG. 19 a vertical sectional view of a third embodiment according to theinvention while the bottom layer having cross beams is transported fromthe assembly site to the installation site;

FIG. 20 a vertical sectional view of the third embodiment according tothe invention after the bottom layer having the cross beams has beenlowered onto the longitudinal bridge girder and after the top concretelayer has been produced;

FIG. 21 the detail C of FIG. 19 ;

FIG. 22 the detail D of FIG. 20 ;

FIG. 23 a vertical sectional view of a fourth embodiment according tothe invention after the bottom layer having cross beams has been loweredat the installation site;

FIG. 24 a vertical sectional view of the fourth embodiment according tothe invention after the conveyor device has been removed from theinstallation site;

FIG. 25 a vertical sectional view of the fourth embodiment according tothe invention after a first top concrete layer has been produced;

FIG. 26 a vertical sectional view of the fourth embodiment according tothe invention after the second top concrete layer has been applied;

FIG. 27 the detail E of FIG. 23 ;

FIG. 28 a sectional view along the line XXVIII-XXVIII of FIG. 27 ;

FIG. 29 the detail F of FIG. 23 ;

FIG. 30 a sectional view along the line XXX-XXX of FIG. 29 ;

FIG. 31 a view of a fifth embodiment according to the invention afterthree prefabricated segments of the bottom layer having cross beams havebeen laid at the assembly site;

FIG. 32 a view of the fifth embodiment according to the invention aftera first top concrete layer has been applied at the assembly site;

FIG. 33 a view of the fifth embodiment according to the invention whilethe bottom layer having cross beams and a first top concrete layer for aconstruction section of the deck slab are transported from the assemblysite to the installation site;

FIG. 34 a view of the fifth embodiment according to the invention afterthe bottom layer having cross beams and a first top concrete layer for aconstruction section of the deck slab has been lowered at theinstallation site;

FIG. 35 a longitudinal view of the fifth embodiment according to theinvention immediately before the bottom layer having cross beams and thefirst top concrete layer for a construction section of the deck slab islifted at the assembly site;

FIG. 36 a longitudinal of the view of the fifth embodiment according tothe invention after the bottom layer having cross beams and a first topconcrete layer for a construction section of the deck slab has beendeposited at the installation site;

FIG. 37 a longitudinal view of the fifth embodiment according to theinvention after the deck slab has been completed;

FIG. 38 a view of a sixth embodiment according to the invention whilethe bottom layer having cross beams is transported for a constructionsection of the deck slab from the assembly site to the installation siteand

FIG. 39 a view of a sixth embodiment according to the invention afterthe bottom layer having cross beams has been deposited for aconstruction section of the deck slab at the installation site.

The first embodiment of the method according to the invention isdepicted in the FIGS. 1 to 13 . According to FIG. 1 , there is erectedat the assembly site 31 a formwork 23 on mounting girders 20. The topsurface of the formwork 23 has the same shape as a bottom surface 19 ofa bottom layer 2 of a construction section. In this exemplaryembodiment, in the first method step, the lower longitudinal andtransverse reinforcement for the first construction section are laid onthe formwork 23. For reasons of clarity, and because the embodiment ofthe reinforcement of deck slabs 1 having a top concrete layer 3 can beassumed as known, the reinforcement is not depicted in this exemplaryembodiment. Subsequently, there are positioned on the formwork 23 threecross beams 21, which are pre-fabricated as prefabricated beams 27. Thecross beams 21 are in this example arranged at an angle of 90° to thelongitudinal axis of the bridge 4. In another embodiment example itwould be possible that the cross beams were arranged at an angle of 80°to the longitudinal axis of the bridge. The cross beams 21 maypreferably be produced from reinforced concrete.

In the longitudinal direction of the bridge 4, there are shiftedlongitudinal edge beams 28 to simplify in a later method step theconcreting works when introducing the top concrete layer 3. The crossbeams 21 as well as the longitudinal edge beams 28 are equipped withstarter bars. The deck slab 1 in this embodiment example has twohaunches in the final condition.

These haunches are to be reproduced already in the production of thecross beams 21 and in the production of the formwork 23.

In the next method step, concrete for the production of the bottom layer2 is introduced according to FIG. 2 . The lower longitudinal andtransverse reinforcement 27 as well as the starter bars of theprefabricated beams 27 are then embedded in concrete. The bottom layer 2is in this example produced having a constant thickness. It would alsobe possible to produce the bottom layer 2 having a variable thickness inorder to reduce the weight of the bottom layer 2 for a constructionsection of the deck slab. The bottom layer 2 for the first constructionsection has eight recesses 16.

According to FIG. 3 , a conveyor device 10 is moved in the next methodstep on a longitudinal bridge girder 5 to the assembly site 21. Thelongitudinal bridge girder 5 in the first embodiment example is composedof two steel girders 9. The steel girders 9 may be connected bytransverse bracing or transverse girders, which are not depicted in thisembodiment example for reasons of clarity. The conveyor device 10 is inthis example composed of a spatial frame construction 49 made fromsteel. Alternatively, the conveyor device 10 could also be composed of atruss construction. The conveyor device 10 has eight wheels 8. Movingthe conveyor device 10 is realized by a rolling process of the wheels 8in the two lanes 7 configured on the top surface 18 of the longitudinalbridge girder 5. The two lanes 7 are each arranged in-between thebracing means 6. The conveyor device 10 may advantageously be moved tothe assembly site 31 only after the reinforcement has been laid, theprefabricated beams 27 have been shifted and the concrete for the bottomlayer 2 has been introduced, as the laying of the reinforcementsupported by a crane and the shifting of the prefabricated beams 27 aswell as the introducing of the concrete for the bottom layer 2 carriedout by means of a concrete pump would be easier to realize. At theassembly site 31, additional means may make it possible that theconveyor device may drive across the cross beams 21 and thereinforcement.

The bottom layer 2 having the cross beams 21 and the longitudinal edgebeams 28 is lifted from the conveyor device 10 after the concrete hashardened and is then transported from the assembly site 31 to theinstallation site 32.

FIG. 4 shows in a view that the bottom layer 2 is lowered at theinstallation site 32. In FIG. 4 , there is depicted a state immediatelybefore supporting the bottom layer 2 onto the longitudinal bridge girder5. The weight of the bottom layer 2 having the cross beams 21 is in thiscondition introduced by the tendons 11 into the conveyor device 10. Thebottom layer 2 having the cross beams 21 and the longitudinal edge beams28 may be classified as a ribbed base plate 26 in a statics point ofview. The net weight of the bottom layer 2 is introduced via astructural bending action in the bottom layer 2 into the cross beams 21and in the edge regions also partly into the longitudinal edge girders28. The cross beams 21 absorb the weight of the bottom layer 2 and ofthe longitudinal edge girder 28 and transmit it to the anchors 14.Within the anchors 14, the net weight of the ribbed base plate 26 istransmitted to the lower end points 13 of the tendons 11.

The upper end points 12 of the tendons 11 are attached to the conveyordevice 10. The conveyor device 10 is positioned at the installation site32 such that the recesses 16 are arranged above the bracing means 6arranged at the top surface 18 of the longitudinal bridge girder 5. Thewheels 8 may be blocked after the precise positioning of the conveyordevice 10 at the installation site 32 to prevent the conveyor device 10from rolling away. Fixing the conveyer device 10 at the installationsite 32 may also be realized by way of a temporary connection of theconveyor device 10 to the longitudinal bridge girder 5 or by othermeasures.

In FIG. 5 there is depicted a vertical section through the conveyordevice 10 positioned at the installation site 32. The ribbed base plate26 is situated at a superelevated position, as during the movement ofthe conveyor device 10 from the assembly site 31 to the installationsite 32 there should be prevented any collision with the bracing means6. The wheels 8 of the conveyor device 10 are arranged in the lanes 7configured between the bracing means 6 on the top surface 18 of thelongitudinal bridge girder 5. The weight of the conveyor device 10 andof the ribbed base plate 26 is transmitted from the wheels 8 to thelongitudinal bridge girder 5.

A sectional view corresponding to FIG. 5 after the ribbed base plate 26has been lowered is depicted in FIG. 6 . After being lowered, the ribbedbase plate 26 is supported on the longitudinal bridge girder 5.Depending on the basic geometrical dimensions of the ribbed base plate26, the configuration of the reinforcement and the dimensions of thecross beams 21, the ribbed base plate 26 may be supported on thelongitudinal bridge girder 5 in such a way that the tendons 11 will becompletely relieved. It would, however, also be possible to support theribbed base plate 26 on the longitudinal bridge girder 5 in such a waythat only a part of the weight of the ribbed base plate 26 is supportedon the longitudinal bridge girder 5 and that the remaining part of theweight of the ribbed base plate 26 is absorbed by the tendons 11 andintroduced into the conveyor device 10.

FIG. 7 shows in a detailed view a wheel 8 of the conveyor device 10,which is arranged between the bracing means 6 in a lane 7 on the topsurface 18 of longitudinal bridge girder 5. Strips 22 are adhered ontothe top surface 18 of the longitudinal bridge girder 5. The strips 22may, for example, be made from an elastomeric material. In a cross beam21, there is installed an anchor 14 for connection to the lower endpoint 13 of a tendon 11. This anchor 14 is composed of a steel slab 35and a threaded nut 36, which is welded to the top surface of the steelslab 35. At the outer surface of the threaded nut 36 there is attached asleeve tube 37. At the lower end point 13 of the tendon 11 there isconfigured a thread providing for attachment of the tendon 11 within theanchor 14.

FIG. 8 shows a detailed view corresponding to FIG. 7 after the ribbedbase plate 26 has been lowered and the ribbed base plate 26 has beensupported on the top surface 18 of the longitudinal bridge girder 5.When transmitting the weight of the ribbed base plate 26 from theconveyor device 10 onto the longitudinal bridge girder 5, the strips 22are pressed together. Pressing these strips 22 together makes itpossible to compensate for any constructional inaccuracy between thebottom surface 19 of the bottom layer 2 and the top surface 18 of thelongitudinal bridge girder 5. A second important function of the strips22 is the production of a sealing between the bottom surface 19 of thebottom layer 2 and the top surface 18 of the longitudinal bridge girder5. The gap 24 between the bottom surface 19 of the bottom layer 2 andthe top surface 18 of the longitudinal bridge girder 5 corresponding inheight to the thickness of the strips 22 pressed together should befilled with grout or concrete to ensure protection against corrosion ofthe top surface 18 of the longitudinal bridge girder 5.

According to FIG. 9 , a top concrete layer 3 is applied onto the loweredribbed base plate 26. The surface of the ribbed base plate 26 should bemade as rough as possible such that there is given rise to a goodbracing effect within the joint between the ribbed base plate 26 and thetop concrete layer 3. The weight of the top concrete layer 3 is in thisworking step transmitted to a smaller extent via the structural bendingaction of the ribbed base plate 26 to the two steel girders 9 of thelongitudinal bridge girder 5 and to a larger extent via the tendons 11into the conveyor device 10. The weight of the top concrete layer 3 thatis absorbed by the conveyor device 10 will be introduced via the wheels8 into the longitudinal bridge girder 5.

According to FIG. 10 , there is installed in the next step a device 15for moving the conveyor device 10 on the top concrete layer 3, once thetop concrete layer 3 has reached a predetermined minimum rigidity. Thenin the next step of the method according to the invention the tendons 11are disassembled. A complete disassembly of the tendons 11, which isdepicted in FIG. 10 , is not absolutely essential. Releasing theconnections between the lower end points 13 of the tendons 11 and theanchors 14 installed in the ribbed base plate 14 is sufficient tointroduce the entire weight of the deck slab 1 via a structural bendingaction into the longitudinal bridge girder 5 and to relax the conveyordevice 10. Following the transfer of weight of the ribbed base plate 26and the top concrete layer 3, which together form a construction sectionof the deck slab 1, the weight of the conveyor device 10 is shifted fromthe wheels 8 onto the device 15 for moving the conveyor device 10 on thesecond top concrete layer 3. This shift may, for example, as depicted inFIG. 10 , be realized by lifting and turning over the wheels 8.Subsequently, the conveyor device 10 may be moved by means of the device15 for moving the conveyor device 10 on the top concrete layer 3 to theassembly site 31 to optionally pick up there a further ribbed base plate26.

A bridge 4, which comprises two abutments 33, five pillars 34 and onelongitudinal bridge girder 5, is depicted in FIG. 11 to FIG. 13 . Theconveyor device 10 is moved by way of winches to the assembly site 31,which is here arranged above one of the two abutments 33. At theassembly site 31, the ribbed base plate 26, which is composed of thebottom layer 2, the cross beams 21 and the longitudinal edge beams 28,is attached at the conveyor device 10 by means of tendons 11. The ribbedbase plate 26 is lifted to prevent any contact with the bracing means 6mounted on the longitudinal bridge girder 5 when the conveyor device 10is moved in the longitudinal direction of the bridge 4 and to make itpossible that a construction section already completed of the deck slab1 may be driven on. To make it possible to drive over the constructionsections already completed of the deck slab 1 it is necessary to installthe device 15 for moving the conveyor device 10 on a top concrete layer3.

According to FIG. 12 the conveyor device 10 and the ribbed base plate 26attached thereto are moved in the next method step from the assemblysite 31 to the projected installation site 32. At the installation site32, the ribbed base plate 26 is lowered until the bottom layer 2 restson the top surface 18 of the longitudinal bridge girder 5. Then the topconcrete layer 3 may be applied. After the top concrete layer 3 hashardened, there is installed a device 15 for moving the conveyor device10 on the top concrete layer 3, the tendons 11 are released from theanchors 14 in the prefabricated slabs 2 and the conveyor device 10 isconveyed to the assembly site 31 such that the ribbed base plate 26 maythere be received for the next construction section.

In this embodiment example, the ribbed base plate 26 is attached to theconveyor device 10 by means of tendons 11, while the top concrete layer3 is being applied. Only once the top concrete layer 3 has hardened, theribbed base plate 26 is removed from the conveyor device 10.Alternatively, it would also be possible to configure the ribbed baseplate 26 to be so rigid such that it would be able to carry its own netweight and the weight of the top concrete layer 2. A ribbed base plate26 such configured would make it possible that the connection betweenthe ribbed base plate 26 and the conveyor device 10 is releasedimmediately after the ribbed base plate 26 has been lowered and theconveyor device 10 could be moved back to the assembly site 31. Thiswould enable the acceleration of the production of the deck slab 1. Inthis case, however, there should be installed makeshift lanes 7 on theribbed base plate 26 such that it would be possible for the conveyordevice 10 to drive on the ribbed base plate 26.

The assembly site 31 is in the first embodiment example situated on anabutment 33. It may also be advantageous to move the assembly site 31onto the bridge 4, after the first sections of the deck slab 1 have beenproduced. It may also be advantageous to provide more than one assemblysite 31 to enable longer hardening of the concrete of the bottom layer2. According to FIG. 13 , the remaining sections of the deck slab 1 ofthe bridge 4 are produced using the method according to the invention.Subsequently, the bridge 4 is then completed in the usual manner byapplying a sealing onto the surface of the top concrete layer 3 and bysubsequently applying a deck cover.

In this exemplary embodiment, the weight of the ribbed base plate 26 onthe top concrete layer 3 is introduced from the wheels 8 into thelongitudinal bridge girder 5. Alternatively, it would also be possibleto install supports and to lift the wheels 8 before the top concretelayer 3 is introduced. This may also be of advantage as the supports maybe accommodated in the recesses 16 having smaller dimensions than therecesses 16 required for the accommodation of the wheels 8.

A second embodiment of the method according to the invention is depictedin the FIGS. 14 to 18 . According to FIG. 14 , there are produced on anassembly site 31 on a framework 23 three segments 17 of a bottom layer 2having cross beams 21, which are arranged in the transverse direction inregard to the longitudinal axis of the longitudinal bridge girder 5. Inthe three segments 17 of the bottom layer 2, there are contained thelower longitudinal and transverse reinforcement, the shear reinforcementand a part of the upper longitudinal and transverse reinforcement. Forreasons of clarity, the reinforcement is not depicted in this embodimentexample. Support constructions 29 are arranged between the segments 17.The support constructions 29 are composed of steel tubes welded to themounting girders 20. At the upper end points of the supportconstructions 29, there are mounted launching gantries 30. The launchinggantries 20, for example, are configured as roller bearing or slidebearing such that a conveyor device 30 may be shifted on the launchinggantries 30 in the longitudinal direction along the longitudinal bridgegirder 5 and on the assembly site 31.

After the concrete of the bottom layer 2 has hardened, a conveyor device10 will be moved to the assembly site 31, the three segments 17 of thebottom layer 2 will be attached using tendons 11 to the conveyor device10, will be lifted and transported to the installation site 32.According to FIG. 15 , the three segments 17 of the bottom layer 2 arelowered at the installation site 32 in such a way that the edges of thesegments 17 are supported on the steel girders 9 of the longitudinalbridge girder 5.

FIG. 15 shows that there are formed by the three segments 17 of thebottom layer 2 two cantilevering slabs and a slab arranged between thetwo steel girders 9 of the longitudinal bridge girder 5. These threeslabs should be separated from one another to make it possible to conveythe conveyor device 10 in the longitudinal direction of the bridge 4 andto lower the bottom layer 2.

For this reason it is also not possible to lay the entire reinforcementat the assembly site 31. The upper transverse reinforcement required forconnecting the cantilevering slabs and the slab arranged between thesteel girders 9 of the longitudinal bridge girder 5 may only be laid atthe installation site 32 after the bottom layer 2 has been lowered.

A bridge 4 comprising two abutments 33, five pillars 34 and onelongitudinal bridge girder 5 is depicted in the illustrations FIGS. 16to 18 . As shown in FIG. 16 , the support constructions 29 are mountedon the longitudinal bridge girder 5 and on the assembly site 31, whichis situated on one of the two abutments 33. The conveyor device 10,which is configured as a spatial frame construction 49, is moved withthe aid of winches to the assembly site 31, which is here arranged aboveone of the two abutments 33. At the assembly site 31, the bottom layer 2is attached by means of tendons 11 to the conveyor device 10. The bottomlayer 2 is mounted in a lifted superelevated position to prevent anycontact with the bracing means 6 mounted on the longitudinal bridgegirder 5 when conveying the conveyor device 10 in the longitudinaldirection of the bridge 4 and to make it possible to drive on the topconcrete layer 3 of construction sections already completed of a deckslab 1.

According to FIG. 17 , the conveyor device 10 and the bottom layer 2suspended therefrom are moved from the assembly site 31 to the scheduledinstallation site 32 in the next method step. At the installation site32, the bottom layer 2 is lowered until the edges of the segments 17 ofthe bottom layer 2 rest on the upper flanges of the steel girders 9 ofthe longitudinal bridge girder 5. Then the top concrete layer 3 may beapplied. After the top concrete layer 3 has been hardened, the tendons11 are released from the bottom layer 2 and the conveyor device 10 isconveyed to the assembly site 31, such that the bottom layer 2 may bemounted for the next construction section at the conveyor device 10.

The assembly site 31 is situated in this embodiment example on anabutment 33. It may also be advantageous that the assembly site 31 ismoved to the bridge 4 after the first sections of the deck slab 1 havebeen produced.

According to FIG. 18 all support constructions 29 are removed after theproduction of the deck slab 1 by cutting off the steel profiles in thevicinity of the surface of the top concrete layer 3. Subsequently, thebridge 4 is completed in the usual manner by applying a sealing onto thesurface of the top concrete layer 3 and by subsequently applying a deckcover.

A third embodiment of the method according to the invention is depictedin the illustrations FIGS. 19 to 22 .

FIG. 19 shows a vertical section through a conveyor device 10, which isconfigured as a spatial frame construction 49, and through a bottomlayer 2 composed of three segments 17, during the transport from theassembly site 31 to the installation site 32. The conveyor device 10 ismoved on launching gantries 30, which are mounted on supportconstructions 29. The three segments 17 of the bottom layer 2 areproduced at the assembly site 31 having cross beams 21. Within the crossbeams 21, there are installed cladding tubes 38, which are installed inthe bracing wire produced in a later step.

During transport to the installation site 31, the segment 17 arrangedbetween the steel girders 9 is in a raised position to prevent collisionwith the bracing means 6 welded to the steel girders 9 and theconstruction sections already completed of the deck slab 1. The segment17 depicted in FIG. 19 at the left hand-side is in a raised andlaterally shifted outwards position during the transport of the bottomlayer 2 to the installation site 32 in order prevent a collision of thecross beams 21 with the support constructions 28 and the bracing means6. The segment 17 depicted in FIG. 19 at the left-hand side is in araised and turned position during the transport of the bottom layer 2 tothe installation site 32 to prevent a collision of the cross beams 21with the support construction 29 and the bracing means 6.

At the installation site 32, the three segments 17 of the bottom layer 2are brought into the scheduled position. According to FIG. 20 , there isrequired lowering the segment 17 arranged in-between the steel girders9, lowering and shifting transversally to the right the segment 17arranged in FIG. 19 at the left-hand side as well as lowering andturning the segment 17 arranged in the FIG. 19 at the right-hand side.The scheduled position depicted in FIG. 20 is reached when the upperedges of the cross beams 21 are in a horizontal position and when thefront faces of the cross beams 21 touch. Using the method according tothe invention it is also possible to reach a different position of thesegments, for exampling having a constant transversal inclination, inthe scheduled final position.

According to FIG. 21 , a conveyor device 10 is mounted on launchinggantries 30. The launching gantries 30 are, for example, configured asroller bearings or as sliding bearings such that the conveyor device 10may be shifted in the longitudinal direction along the longitudinalbridge girder 5 of the bridge 4. The launching gantries 30 are attachedat the upper end points of support constructions 29. The supportconstructions 29, which herein are configured as steel profiles, areconnected in a flexurally rigid manner to the upper flanges of the steelgirders 9 of the longitudinal bridge girder 5. The bottom layer 2 isdepicted in FIG. 21 in a raised or superelevated, respectively, positionand in FIG. 2 in a lowered position. In the superelevated position, thebottom layer 2 should be raised so much so that it is possible to driveon the bracing means 6 and the top concrete layer 3 of constructionsections already completed. In the lowered position according to FIG. 22, the wheels of the bottom layer 2 are supported on the upper flanges ofthe steel girders 9 of the longitudinal bridge girder 5. FIG. 21 showsthat within the cross beams 21, which are connected to the segments ofthe bottom layer 2, there are arranged cladding tubes 38.

According to FIG. 22 , the segment depicted at the left-hand side ofFIG. 19 of the bottom layer 2 is moved as far to the right until thefront faces of the cross beams 21 touch one another. If the front facesof the cross beams 21 have been very accurately produced orpost-finished, then contact splice may be performed. Alternatively, alsothe production of a splice connection with a coupling of the claddingtubes 38 and a grouting joint would be possible. After the segments ofthe bottom layer 2 have been accurately aligned, the top concrete layer3 is produced. Subsequently, bracing wires 39 are inserted into thecladding tubes 38. By tensioning the bracing wires 39, a transversepreload may be applied onto the deck slab 1.

According to FIG. 22 , the steel profiles of the support constructions29 are embedded into concrete when applying the top concrete layer 3.The tendons 11 are protected by means of a sheath tube 37 against directcontact with the top concrete layer 3. This enables removal of thetendons 11 after the top concrete layer 3 has been hardened and re-useof the tendons 11 in the next construction section. The steel profilesare cut off in the vicinity of the surface of the top concrete layer 3after the top concrete layer 3 has been hardened and the launchinggantries 30 have been disassembled.

A fourth embodiment of the method according to the invention is depictedin the illustrations FIGS. 23 to 30 .

FIG. 23 shows a vertical section through a conveyor device 10, which isconfigured as a spatial frame construction 49, and a bottom layer 3composed of three segments 17 at the installation site 32. The threesegments 17 of the bottom layer 2 are attached at the conveyor device 10by means of tendons 11. The segments 17 are in this embodiment examplenot supported on the longitudinal bridge girder 5 composed of twoprestressed concrete beams 40 but rather positioned next to theprestressed concrete beams 40. This has the advantage that thelongitudinal bridge girder 5 may be configured having a largerstatically effective depth. After the bottom layer 2 having cross beams21 has been positioned as scheduled, the three segments 17 are connectedto one another via the prestressed concrete beams 40 by means ofstructural steel connections. In order to realize the structural steelconnection, there are installed steel panels 42 within the cross beams21. At the installation site 32, these steel panels 42 are connected toone another in a flexurally rigid manner with additional steel panels 35and screw connections 41. After the three segments 17 have beenconnected in a flexurally rigid manner, the tendons 11 are relaxed anddismantled. The conveyor device 10 is no longer required at theinstallation site 32 and may be moved back to the assembly site 31.

FIG. 24 shows the installation site 32 after removal of the conveyordevice 10.

In the next working step according to FIG. 25 , the supportconstructions 29 and the launching gantries 30 are removed at theinstallation site. A first top concrete layer 3 is applied onto thebottom layer 2. The weight of the top concrete layer 3 is introducedfrom the bottom layer 2 into the cross beams 21 and from these to theprestressed concrete beams 40. The structural steel connection of thecross beams 21 should be able to absorb any stresses arising. If thefirst top concrete layer 3 reaches a predetermined concrete compressionstrength, there is applied according to FIG. 26 onto the first topconcrete layer 3 a second top concrete layer 3. After the concrete ofthe top concrete layers 3 has hardened, the bottom layer 2, the crossbeams 21, the first top concrete layer 3 and the second top concretelayer 3 are to be considered a construction component produced in amonolithic way, in combination forming the deck slab 1.

The detail E of FIG. 23 is depicted in FIG. 27 and FIG. 28 , showing thestructural steel connection of the two cross beams 21. In the two crossbeams 21, there are installed steel panels 42 projecting beyond thefront faces of the cross beams 21. Upon lowering the bottom layer 2 andthe cross beams 21, the steel panels 42 are supported on the prestressedconcrete beams 40. Subsequently, there is produced by using two steelslabs 35 and screw connections 41 a flexurally rigid connection of thetwo cross beams 21.

An alternative embodiment for producing a flexurally rigid connection ofthe two cross beams 21 is shown in the FIG. 29 and the FIG. 30 . Thereis installed in the prestressed concrete beam 40 a steel panel 42. Frontfaces 43 are welded to the steel panel 42 at the left and right side. Atthe front faces of the cross beams 21, there are attached front faces 43made from steel, which are connected by means of starter bars notdepicted in the cross beams 21. Upon lowering the bottom layer 2 havingthe embedded cross beams 21, there is produced a flexurally rigidconnection of the cross beams 21 with the prestressed concrete beam 40by way of the screw connections 41. Such a connection may also beadvantageous if only cantilevering segments 17 are to be connected to alongitudinal bridge girder 5 having a box-section-like cross-section.

A fifth embodiment of the method according to the invention is depictedin the illustrations FIG. 31 to FIG. 37 .

According to FIG. 31 at the assembly site 31 three prefabricatedelements 47 are laid on mounting beams 20. Each prefabricated element 47is composed of three prefabricated slabs 50 and one cross beam 21configured as prefabricated beam 27 and connecting the threeprefabricated slabs 50 one to another. The bottom layer 2 is formed inthis mounting state of three segments 17.

In the next working step, there is laid a reinforcement onto the bottomlayer 2 and there is produced a first top concrete layer on theprefabricated slabs 50. The three segments 17 of the bottom layer 2 arejoined to one segment 17 by the first top concrete layer 3. FIG. 32shows the state at the assembly site 31 after the first top concretelayer 3 has been produced.

FIG. 33 shows the transport of the bottom layer 2 having cross beams 21and a first top concrete layer 3 for a construction section of the deckslab 1 from the assembly site 31 to the installation site 31. Thetransport is carried out using a conveyor device 10. The conveyor deviceis composed of a front part 44 and a rear part 45, which are configuredas frame constructions 49. The front part 44 and the rear part 45 of theconveyor device 10 are connected to one another by way of twolongitudinal girders 46. The conveyor device 10 is moved in thelongitudinal direction of the bridge 4 on support constructions 29,which are situated on longitudinal bridge girder 5, which is in thisexample composed of two steel girders 9. The weight of the bottom layer2 having the cross beams 21 and the first top concrete layer 3 isintroduced in this transport state into six tendons 11. The lower endpoints 13 of the tendons 11 are arranged within the cross beams 21. Theupper end points 13 of the tendons 11 are attached at the top surface ofhydraulic hollow piston jacks 48. During transport, the bottom layer 2having the cross beams 21 and the first top concrete layer 3 is in araised position to prevent any contact of the cross beams 21 with thebracing means 6, which are not depicted in FIG. 33 for reasons ofclarity and mounted on the longitudinal bridge girder 5, and to make itpossible to drive on construction sections already completed of the deckslab 1. FIG. 33 shows that the pistons 51 of the hollow piston jacks 48are in an extracted position in order to be able to transport the bottomlayer 2 having the cross beams 21 and the first top concrete layer in araised position.

According to FIG. 34 , the pistons 51 of the hollow piston jack 48 areretracted at the installation site 32 to be able to lower the bottomlayer 20 having the cross beams 21 and the first top concrete layer 3into the scheduled final position. Immediately following the loweringoperation, the lower end points 13 of the tendons 11 may be released andthe conveyor device 10 may be moved from the assembly site 32 to theinstallation site 31 to pick up there a further bottom layer 2 havingcross beams 21 and a first top concrete layer 3 for a furtherconstruction section of the deck slab 1. At the installation site 32,immediately after the conveyor device 10 has left or at a later point oftime, there may be laid the starter bars to a neighbouring constructionsections and the second top concrete layer 3 may be applied. The weightof the additional reinforcement and of the second top concrete layer 3is absorbed by the bottom layer 2, the cross beams 21 and the first topconcrete layer 3. In order to reach the goal of the bottom layer 2, thecross beams 21 and the two top concrete layers 3 in the final conditionof the deck slab 1 behaving like a construction section produced in onepour, it is necessary to configure the surfaces rough and to provide thenecessary starter bars.

A bridge 4 comprising two abutments 33, five pillars 34 and onelongitudinal bridge girder 5 is depicted in the illustrations FIG. 35 toFIG. 37 . As shown in FIG. 35 , the support constructions 29 are mountedon the longitudinal bridge girder 5 and the assembly site 31, which issituated on one of the two abutment 33. The conveyor device 10 iscomposed of a front part 44 and a rear part 45, which are connected toone another by two longitudinal girders 46. On the assembly site 31, thebottom layer 2 having the cross beams 21 and the first top concretelayer 3 is raised by extracting the pistons 51 of the six hollow pistonjacks 48. The bottom layer 2 having the cross beams 21 and the first topconcrete layer 3 is arranged in this condition between the front part 44and the rear part 45 and underneath the longitudinal girders 46 of theconveyor device 10.

According to FIG. 36 , the bottom layer 2 having the cross beams 21 andthe first top concrete layer 3 is moved in the next method step from theassembly site 31 to the installation site 32. At the installation site32, the bottom layer 2 having the cross beams 21 and the first topconcrete layer 3 is lowered until the cross beams 31 are supported onthe top surface 18 of the longitudinal bridge girder 5. To enable thelowering operation of a bottom layer 2 composed of a segment 17 andhaving cross beams 21 and a first top concrete layer 3 at theinstallation site 32, there must not be arranged any constructionelements for connecting the front part 44 and the rear part 45 of theconveyor device 10 underneath the segment 17.

Immediately following the lowering operation, the lower end points 13 ofthe tendons 11 may be released from the cross beams 21 and the conveyordevice 10 may be moved from the installations site 32 back to theassembly site 31 to pick up there a further bottom layer 2 having crossbeams 32 and a first top concrete layer 3 for a further constructionsection of the deck slab 1.

In this embodiment example it is particularly advantageous that at theinstallation site 32 it is not necessary to wait for the top concretelayer 3 to harden. The conveyor device 10 may be moved away from theinstallation site 32 immediately after the bottom layer 2 having thecross beams 21 and the first top concrete layer 3 has been lowered. Inthis way it is possible to produce one construction section of the deckslab 1 per day. Producing the second top concrete layer 3 is independentof the bottom layer 2 having cross beams 31 and first top concrete layerbeing laid and may be realized at any point of time.

According to FIG. 37 , after the production of the deck slab 1, allsupport constructions 29 are removed by cutting off the steel profilesin the vicinity of the surface of the top concrete layer 3.Subsequently, the bridge 4 is completed in the usual manner by applyinga sealing onto the surface of the top concrete layer 3 and subsequentlyapplying a deck cover.

A sixth embodiment of the method according to the invention is depictedin the illustrations FIG. 38 and FIG. 39 .

The bottom layer 2 having cross beams 21 is produced at the assemblysite 31 on a framework 23. The bottom layer 2 having cross beams 21 iscomposed in this embodiment example of one segment 17, as the threecross beams 21 extend across the entire width of the deck slab 1 to beproduced and, in this way, a continuous construction component is beingdeveloped. FIG. 38 shows the transport of the bottom layer 2 havingcross beams 21 for a construction section of the deck slab 1 from theassembly site 31 to the installation site 32. In this embodiment exampleraising the bottom layer 2 having the cross beams 21 is realized byextracting the pistons 51 of the hollow piston jacks 48, which arearranged between the longitudinal girders 46 and the front part 44 orthe rear part 45, respectively, of the conveyor device 10.

According to FIG. 39 , the pistons 51 of the hollow piston jacks 48 areretracted at the installation site to be able to lower the bottom layer2 having the cross beams 21 into the scheduled final position.Immediately after depositing the bottom layer 2 having the cross beams31 at the installation site 32, the lower end points 13 or the upper endpoints 12 of the tendons 11 may be released and the conveyor device 10may be moved to the assembly site to pick up a further bottom layer 2having cross beams 21 for a further construction section of the deckslab 1.

LIST OF REFERENCES

-   1 deck slab-   2 bottom layer-   3 top concrete layer-   4 bridge-   5 longitudinal bridge girder-   6 bracing means-   7 lane-   8 wheel-   9 steel girder-   10 conveyor device-   11 tendon-   12 upper end point of a tendon-   13 lower end point of a tendon-   14 anchor-   15 device-   16 recess-   17 segment of a bottom layer-   18 top surface of a longitudinal bridge girder-   19 bottom surface of a bottom layer-   20 mounting girder-   21 cross beam-   22 strip-   23 formwork-   24 gap-   25 bottom surface of a bottom layer-   26 ribbed base plate-   27 prefabricated beam-   28 longitudinal edge beam-   29 support construction-   30 launching gantry-   31 assembly site-   32 installation site-   33 abutment-   34 pillar-   35 steel slab-   36 threaded nut-   37 sleeve tube-   38 cladding tube-   39 bracing wire-   40 prestressed concrete beam-   41 screw connection-   42 steel panel-   43 front slab-   44 front part of a conveyor device-   45 rear part of a conveyor device-   46 longitudinal girder of a conveyor device-   47 prefabricated element-   48 hollow piston jack-   49 frame construction-   50 prefabricated slab-   51 piston

1-14. (canceled)
 15. A method for the production of a constructionsection of a deck slab for a bridge, wherein: a—there is produced at anassembly site, from reinforced concrete, a bottom layer composed of oneor more segments and having cross beams, which are arranged at an angleof between 70° and 90° to a longitudinal axis of a longitudinal bridgegirder; b—the bottom layer having the cross beams is transported for theconstruction section of the deck slab, using one or more conveyordevice, from the assembly site to an installation site and lowered intoan installation position; c—there is laid onto the bottom layer havingthe cross beams a top concrete layer for the construction section of thedeck slab, wherein there is laid a reinforcement to be arranged withinthe top concrete layer before the application of the top concrete layer;d—the bottom layer having the cross beams is removed for theconstruction section of the deck slab, from the conveyor device, beforeor after the application of the top concrete layer; and e—the conveyordevice is moved away from the installation site and conveyed to theassembly site in order to pick up there a further bottom layer havingcross beams for a construction section of the deck slab.
 16. A methodaccording to claim 15, wherein the bottom layer having the cross beamsis removed for the construction section of the deck slab after beinglowered from the conveyor device, the conveyor device is moved away fromthe installation site and only then the top concrete layer is beingapplied thereupon.
 17. A method according to claim 15, wherein the crossbeams are produced in advance as prefabricated beams, are laid on theassembly site and only then the bottom layer is being produced.
 18. Amethod according to claim 15, wherein the bottom layer is produced fromprefabricated slabs and the cross beams are connected to theprefabricated slabs by way of welding, screwing, or starter bars.
 19. Amethod according to claim 15, wherein there are arranged within thecross beams anchors for lifting the bottom layer and the cross beamsand/or there is arranged in one of the cross beams a tendon in thelongitudinal direction of that cross beam.
 20. A method according toclaim 15, wherein there are connected to one another two cross beams,which are arranged in different segments, by way of a structural steelconnection.
 21. A method according to claim 15, wherein the top concretelayer is applied in two operations and a second part of the top concretelayer is produced only after a first part of the top concrete layer hasreached a predetermined minimum rigidity.
 22. A method according toclaim 15, wherein the bottom layer and/or the cross beams are producedhaving one or more haunches.
 23. A method according to claim 15, whereinthe bottom layer and/or the cross beams are produced having a variablethickness.
 24. A method according to claim 15, wherein a segment of thebottom layer having cross beams is shifted transversally to thelongitudinal axis of the longitudinal bridge girder and/or rotated inregard thereto after being raised at the assembly site, is transportedfrom the assembly site to the installation site in this shifted and/orrotated position and is then installed at the installation site by crossshift and/or a rotation into the scheduled installation position.
 25. Amethod according to claims 15, wherein there is connected at theassembly site a bottom layer composed of two or more segments and havingcross beams via a first top concrete layer or an alternative techniqueof connection to a bottom layer comprising one segment and having crossbeams.
 26. A method according to claim 15, wherein: the bottom layerhaving the cross beams is produced as a segment; the conveyor device ismade of a front part, a rear part and two or more longitudinal girders;the front part and the rear part of the conveyor device are connected toone another by the two or more longitudinal girders; the front part andthe rear part of the conveyor device are moved on support constructions;the bottom layer having the cross beams is arranged between the frontpart and the rear part and underneath the longitudinal girders of theconveyor device; and there will not be arranged any constructionelements for connecting the front part and the rear part of the conveyordevice underneath the bottom layer having the cross beam during thelowering operation at the installation site.
 27. A method according toclaim 15, wherein: the conveyor device is made of a front part and arear part and two or more longitudinal girders; wherein for shifting theconveyor device in order to produce a next construction section of adeck slab, the front part and the rear part of the conveyor device aremoved on support constructions in the longitudinal direction of thebridge; wherein the front part and the rear part of the conveyor deviceare connected to one another by the two longitudinal girders; and thereis created at the longitudinal girders a construction for lifting and/orlowering the bottom layer having the cross beams, which is arrangedbetween the front part and the rear part and underneath the longitudinalgirders of the conveyor device.
 28. (canceled)
 29. A method according toclaim 15, wherein the bottom layer is produced from prefabricatedelements, wherein the prefabricated elements comprise two or moreprefabricated slabs and one cross beam connecting the at least twoprefabricated slabs with each other, wherein the prefabricated elementsare laid on mounting girders at the assembly site and the prefabricatedelements are connected to a segment.